1. Field of the Invention
The present invention relates to a flip or folder type terminal and more particularly to a circuit and method for processing a malfunction of a hall effect switch used for recognition of an open/close state of a flip or a-folder of a flip or folder type terminal.
2. Description of the Related Art
Generally, a mobile terminal (e.g., a portable phone) is classified into three types, i.e., a bar type, a flip type, and a folder type. In the flip type and folder type terminal, a magnet is attached to the flip or the folder, respectively, and a hall effect switch is mounted on a position opposite to the flip or the folder. When the flip or the folder is opened, the hall effect switch moves away from the magnet, while when it is closed, the hall effect switch moves nearer to the magnet. Accordingly, the hall effect switch senses a change of a magnetic field generated from the magnet.
The hall effect switch is a kind of logic IC (Integrated Circuit) including a timer that operates at predetermined intervals. That is, the hall effect switch senses the strength of the magnetic field at the predetermined intervals, and outputs a high or low level signal according to the sensed strength of the magnetic field. Thus, if the high level signal is input to an a control section of the mobile terminal, the control section recognizes that the flip or folder is opened. On the contrary, if the low level signal is inputted, the control section recognizes that the flip or folder is closed.
FIG. 1 is a schematic diagram of an apparatus for recognizing an open/close state of a flip or a folder in a conventional terminal. In FIG. 1, a hall effect switch senses a change of a magnetic field according to an opening/closing of the flip or the folder, and provides through its output terminal 100 a high or low level signal to a flip/folder-state input terminal 200 of a control section as a result of sensing. A resistor R1 and a capacitor C1 are connected to an output terminal 100 of the hall effect switch and the flip/folder-state input terminal 200 of the control section. Here, the resistor R1 is a pull-up resistor of which one terminal is connected to a supply voltage Vcc. The capacitor C1 is a ripple-removing capacitor of which one terminal is connected to ground.
The operation of the apparatus illustrated in FIG. 1 will be described with reference to FIGS. 2A and 2B herein below.
FIG. 2A illustrates a normal-state signal output from the output terminal of the hall effect switch 100. The falling edge S1 illustrated in FIG. 2A represents a closed flip or folder. Specifically, in an open state of the flip or folder, the output terminal of the hall effect switch 100 outputs a high level signal, and if the user closes the flip or folder, the output terminal of the hall effect switch 100 outputs a low level signal.
FIG. 2B illustrates an abnormal-state signal output from the output terminal of the hall effect switch 100. When a user makes a call, a magnetic field may be produced due to current flowing through a battery. The hall effect switch may also sense such a change of the magnetic field. In other words, the hall effect switch may also sense changes in the magnetic field produced by components and reasons other than changes caused by the opening/closing of the flip or the folder. As a result, the flip/folder-state input terminal of the control section 200 may incorrectly sense an open/close state of the flip or the folder.
As illustrated in FIG. 2B, an abnormal-state signal is output, for example, in a manner that the output of the hall effect switch changes from the high level to the low level, and then changes from the low level to the high level at short time intervals, and vice versa.
As described above, if the flip/folder-state input terminal of the control section 200 incorrectly recognizes an open/close state of the flip or the folder, it causes a great inconvenience in use. For example, in a portable phone, a call may be abruptly disconnected. Also, even when using other functions of the terminal, the corresponding functions cannot be properly performed and will be terminated.
Therefore, a need exists for a system and method for identifying and correcting malfunctions in hall effect switches in flip type and folder type terminals.